Propylene copolymers or terpolymers are commercially used because, with respect to propylene homopolymers, they are often characterized by greater impact resistance, lower rigidity, and better transparency. However, it may be difficult to find an acceptable balance between those properties, particularly when the properties contrast each other. When a certain softness is desired, for example, it may obtained in the presence of a high amount of xylene soluble fractions that make the resulting polymers unsuitable for food contact applications.
Metalized films such as aluminum films have been widely used for their superior decorative properties, gas barrier properties and light-shielding properties.
WO 2003/037981 discloses pipes made from a polypropylene composition obtained by a process carried out in a reactor comprising two interconnected polymerization zones.
The process provides polypropylene compositions with high stiffness and impact resistance suitable for pipes, wherein the propylene composition is a propylene-ethylene-butene-1 terpolymer with an ethylene content ranging from 2-5 wt %.
WO 2009/019169 discloses a propylene ethylene 1-butene terpolymer obtained by a process carried out in a reactor comprising two interconnected polymerization zones. This terpolymer has a xylene soluble fraction higher than 9 wt % and a comonomer content higher than 8 wt %. In particular, when the ethylene content is lower than 2.5 wt % the 1-butene content is higher than 10 wt %. The terpolymers disclosed therein are characterized by a melting temperature Tm higher than or equal to (28.013X+120.5)° C., where X is the value of the weight ratio of ethylene content to the C4-C8 alpha-olefins content.